Nowadays, more and more electronic devices use light-emitting diodes (LEDs) as backlight module. For a common LED backlight module, these LED strings of the LED module are turned on or off under controlling of a control integrated chip (IC), and the control integrated chip and the LED strings are powered by a power source. Usually, when two ends of the LED strings are short-circuited, namely an output of the power source is short-circuited, it is easy to damage the IC. However, general circuits do not have short-circuit protection function for the LED strings.